The proposed studies will provide pilot data suggesting new directions for a more general program concerning the neurobiology of aging in the olfactory system. Olfactory deficits are common in humans during normal aging and in age-related disease states, such as Alzheimer's disease. Whereas at least part of these deficits may be peripheral in nature, it is likely that central mechanisms also deteriorate. Piriform cortex is the main central target of the olfactory bulb and plays a critical role in the identification and recollection of smells. The physiological operation of the piriform cortex circuit has been described in detail in normal (young), adult animals; however, there have been no reports of changes in function with aging. The present proposal addresses this issue and seeks to investigate aging effects on the cellular and synaptic physiology of piriform cortex neurons in the rat. The results of these investigations should help to explain why olfactory function declines with age and possibly suggest treatment strategies for prevention of age-associated sensory losses.